MIDEAST STOCKS-Gulf markets fall; Emaar Properties drops after earnings

* Petchems lead Saudi market down * Dubai Financial Market sinks after earnings * GFH rises on letter of intent with Eshraq * Abu Dhabi's TAQA outperforms on asset sale hope * Qatar's Ezdan falls after Q1 costs increase By Andrew Torchia DUBAI, May 2 (Reuters) - Stock markets in the Gulf fell on Monday after oil prices pulled back and Dubai blue chip Emaar Properties dropped following the release of its first-quarter earnings. Saudi Arabia's index slipped 0.6 percent as petrochemical shares in p